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Shock therapy and surgery saving California’s threatened condors

By Penny Sarchet

Big bird, big problems(Image: John Cancalosi / NaturePL)

IT SHOULD be hard to miss California condors – they are North America’s largest birds, with wingspans of up to 3 metres. But lead poisoning from gun ammunition nearly drove them to extinction in the 1980s. Now, electric shock training and surgery are helping to re-establish these giant birds.

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But to sustain themselves in the wild, condors have to survive for long enough to reproduce. Condors take five to six years to reach maturity, and usually don’t successfully raise young until they have themselves been flying in the wild for seven years.

“As they go in to land at a carcass, or to roost for the night, they just don’t see the power lines”

So conservationists have come up with a shocking solution. The condors are caught several times a year for monitoring and health screening, when they also receive cable aversion training. Artificial utility poles, placed in large training pens, teach the birds to stay clear of cables by giving them a painful electric shock. Before the training was introduced, 66 per cent of released birds died of electrocution. This has now dropped to 18 per cent (Biological Conservation, doi.org/6tb).

Lead poisoning has proved more difficult to deal with. When condors eat carcasses containing lead ammunition, they absorb large quantities of the element. This affects their nervous systems and fertility, and can lead to kidney failure and death.

This work is starting to pay off. In 2000, the annual mortality rate for adult condors was 38 per cent, but between 2001 and 2011, this dropped to an average of 5.4 per cent – just shy of the 5.3 per cent thought to be needed for populations to become stable.

Rideout’s team estimates that the California condors’ average survival time in the wild is now just under eight years. “Although these measures are not sustainable indefinitely, they are essential for now,” he says. “They are truly magnificent birds that are worth every effort we put into recovering them.”

This article appeared in print under the headline “California condor’s shocking recovery”